Process and apparatus for stacking or storing delicate thin webs of material



United States Patent Inventors Willi J. Schmidt Hahn Taunus, Germany; Wolfgang Korneli; Eberhard Werner, Wlesbaden-Biebrich, Germany Appl. No. 753,693

Filed Aug. 19, 1968 Patented Nov. 17, 1970 Assignee Kalle Aktiengesellschaft Wiesbaden-Blebrich, Germany a corporation of Germany Priority Aug. 22, 1967 Germany 1 No. X63167 PROCESS AND APPARATUS FOR STACKING OR STORING DELICATE THIN WEBS OF MATERIAL 11 Claims, 5 Drawing Figs.

US. Cl 242/64 Int. Cl B65h 75/00 Field of Search 242/67.1,

[56] References Cited UNITED STATES PATENTS 423,448 3/1890 Savery 242/64 452,854 5/1891 Smith..... 242/72B 612,958 10/1898 Stone 242/75.3 925,949 6/1909 Rolland 242/75.3 2,796,169 6/1957 Smith 242/47.01 3,056,562 10/1962 Lucke 242/64 Primary Examiner Nathan L. Mintz Attorney-James E. Bryan ABSTRACT: This invention relates to a process and apparatus for stacking or storing delicate thin webs of material in which a web of material is formed into a rotatably mounted stack which contacts a support at least at three contact areas over the entire width of the material, the contact pressure being limited by a resilient effect of the contact areas, and the speed and stress differences of the web occurring when passing the contact areas being compensated by a movable roller which is contacted by the web before it contacts the stack.

Patented Nov. 17, 1970 3,540,669

Sheet 1 of2 INVENTORS WILLI J. SCHMIDT WOLFGANG KORNELI EBERHARD WERNER Patented Na v. 17, 1970 7 3,540,669

Sheet 2 of 2 INVENIQRS WILLI J. scnmor WOLFGANG xonueu k r EBERHARD WERNER BY 57 M4 111;,

ATTORNEYS ofthe invention.

PROCESS AND APPARATUS FOR STACKING R STORING DELlCA'lE THIN WEBS 0F MATERIAL This invention relates to a process and apparatus for stacking or storing delicate thin webs of material, e.g. those of cellulose or plastic film, which are taken over at a tensile stress acting continuously from the lower plies of the web of material through the individual plies to the top ply.

It is knows to wind webs of material of all kinds onto a core, reel, drum or the like. Insofar as materials such as paper or fabric are concerned, the circular type of winding presents minor difficulties since these webs generally can be wound tightly and thus are not damaged. Completely different, however, is the situation in winding delicate thin webs of material,

e.g. in the form of plastic films of a few ;1.. in this case it is not easily possible to produce a tight stable supporting winding construction.

in accordance with the invention, a process is provided in which a web of material is stacked to give a rotatably mounted stack and, at least at three places, is contacted over its entire width, the value of the contact pressure being limited by a resilient effect of the contact areas, and the speed and tension differences oftheweb of material occurring when it passes the contact areas are compensated by a movable support which it contacts before impinging on the stack.

Suitable webs of material for stacking or storing according to the process of the invention are delicate thin cellulose or plastic sheet materials which may be' surface-treated or coated.

Delicate webs of material of such thickness are stacked which usually are subjected to distortion or pleat formation or the like when being wound onto cylindrical winding rolls. I

It has proved advantageous that the width of the web of material to be stacked or stored corresponds at least to the height of the stack. Exceeding the stack height, the width may have any value so that any delicate thin web of material from a production machine can'be stacked according to the process The process of the invention for stackingor storing differs distinctly from a winding-up process since it clearly differs from the conditions of the latter process by the present freedom that themat erial is not forced to yield to the interior.

The number ofthe contact areas substantially depends upon the dimension of the-support and is limited only in that a polygonal form is maintained also after completing the process. A conversion into the circular form must be avoided since thenall disadvantages of circular winding would again become apparent.

The number of the contact areas is at least three or more, but it would be particularly suitable to stack on supports with 4 to 12 contact areas. In the case ofa support diameter of 200 mm., 6 contact areas are used, for example. The number of material is contacted over its entire width since, otherwise,

folds, creases or a moving down of the web cannot be avoided.

The contact areasare resilient and may be mounted on the support or may be a part of the support. The contact areas alone form the contact lines for the stack to be supported.

According to the process of the invention, the web of Stacking or-storing according to the process of the invention necessarily leads to speed variations. A substantial feature of the process is to absorb orcompensate these variations before the web of material impinges. This is achieved in that, before the stacking or storing operation, the compensating function is transferred to a movable support by a movement in the sense of shortening the web of material. The tension differences in the web of material to be stacked are thus also considerably avoided.

The present invention also provides an apparatus for the performance of the process for stacking or storing delicate thin webs of material, which are taken over at a tensile stress acting from the lower plies of the web of material through the individual plies upon the upper one.

Referring to the drawings:

FIG. 1 is a schematic view in elevation of one embodiment of the apparatus ofthe invention,.and

FIGS. 2-5 are perspective views of supports employed in the apparatus ofthe invention.

For placing a stack 2 on adimensionally stable support 1 at least three ribs 4 of a resilient structure or with a resilient indcntable sure surface are provided for the entire width of the web of material 5 and, for compensating the speed and tension differences ofthe web of material 5, a roller 6 is provided which executes an oscillating movement.

There areat least three ribs 4 so that, in elevation, the web of materialis stacked. in the form of a triangle. Stacking or v storing of the web of material 5 also may be performed in any other polygonal form as long as no circular cross section is formed. It has proved advantageous that the width of the web of material tobe stacked or stored corresponds at least to the structure are provided, in the contact areas with the web of i: I

material 5, with a dimensionally stable surface 7., e.g. of metal,

' or synthetic plastic. Care should be taken to ensure a su ff cient distance of the dimensionally'stable surface 7 from the support 1 so that the resilient indentability of the ribs 4 is not impaired. It is thus avoided that, when mountingthe beginning of the web of material 5, nonuniform drawing causes concentrated indentations in the ribs.

The ribs 4 mounted on the support I may have any cross section, e.g. a circular, semicircular, angular or oval cross section. It is also possible to form the ribs 4 as hollow sections or as hollow sections with an adjustable pneumatic internal pres sure. The cross section of the support 1 may have any basic form, but preferably it has a circular crosssection.

The operation of the roller 6 is as follows:'in its nonoperating position and'without the action of the mean web tension of the material concern'edwith. avoidance of too low or too By means of the specific resiliency of the Contact areas,

high a tensionthe swinging arms 8 forming the connection sion in the direction, and having the value, of the resultant force R resulting from the lateral forces in the web material will already deflect the roller 6 from its vertically suspended position and pivot it in a range resulting from the speed variations ofthe web of material 5.

The tension differences in the web of material 5 also are simultaneously compensated or at least suppressed to such an extent that the stack formation cannot be impaired by stress concentrations in the web of material 5. The weight of the roller 6'advantageously has such a value that the forces available for deflectionare sufficient to overcome the acceleration and retardation forces opposed to the roller movement because of the mass moment ofinertia.

It has proved advantageous to provide a vertical distance of a few centimeters between the roller 6 and the stack 2 and to maintain it approximately constant. This entails theadvantage that the conditions during stacking, particularly the distance of the free web of material 5, remain constant. Direct contact of the stack 2 with the roller 6 would be disadvantageous because ofthe prompt mechanical influence of the stack 2.

The distance may be provided by advancing the axis 13 or, in the case of a stationary position of the axle ll of the stack 2, may be provided by changing-the pivot 9 of the roller 6 or by other known means. Advancing may be performed manually or automatically by means of known scanning devices, e.g. light barriers, switches with scanning rolls, and the like.

In the case of a relatively thin layer thickness ofstack 2 or in the case of a suitable web of material 5. it also is possible to dispense with the advancing movement and to provide a sufficient distance at the beginning.

The apparatus of the invention also may be employed when,

' before the web of material is transferred to the stack 2, a stamillimeters. lt must be adapted to the characteristics of the web of material to be stored or stacked and normally exhibits decreasing values with an increasing stack height.

The advantages achieved with the invention reside particularly in the fact that, in the predominant part ofthe stack, the

web of material 5. apart from its own weight,is pressure-free stacked in the form ofindividual plies and practically speaking cannot be damaged, and that, in the area of the ribs 4, the pressure between the individual plies is only slightly above their own weight. As experience has shown, the web of material also is not damaged in these latter areas.

. Even in the case of incorrect employment of the process of the invention by too great a tensile stress during stacking of the upper plies of the stack 2, the lower plies may freely sink downward between-the individual ribs 4; but the pressure in the contact range does not reach a value above that predetermined by the elasticity of the ribs 4.

Further substantial advantages reside in the fact that the air layer first taken along during stacking is immediately displaced to the pressure-free zone of the stack 2 and can slowly pass from there outward to the front side, whereas in the carrying range above the ribs 4 an almost direct contact is obtained between the individual plies. The good surface adhesion produced therewith considerably limits the possibility ofa relative displacement of the plies to one another, which may be initiated by the continuous transfer of the tensile stress, and this permits operation with a substantially lower tensile stress than in the cascof the windings of the prior art without the layers beinglaterally displaced or the lower layers being addi- The vertical distance between the roller 6 and the stack 2 is limited to a few centimeters and can be maintained approximately constant by advancing the axle ll about the axis 13. Advancing is performed manually or automatically by known scanning devices, not illustrated. It also is possible to perform the advancing movement at the pivot 9 ofthe roller 6.

Support-ing of the stack 2 is performed substantially indirectly by the support 1 which, in this case, has six semicircular ribs 4 which are positioned transversely to the stack direction over the entire width of the web ofmaterial. The ribs 4 have a resilient structure or have resilient indentable surfaces.

The ribs 4 are mounted on the support 1; they also may be a part of the support 1.

FIGS. 2, 3, 4, and 5 show some embodiments of the ribs 4 which, for example, are mounted on a cylindrical support 1. In FIG. 2, dimensionally stable surfaces 7 of metal or synthetic plastic are adapted to and mounted on the resilient ribs 4 where the web of material to be stackedcontaets the ribs and, furthermore,- the dimensionally stable surface 7 is sufficiently distanced from the, support 1 so that the resilient indentability of the ribs is not impaired. H6. 3 shows ribs 4 of a resilient structure with full profile consisting, for example, of rubber sponge, which are mounted'on the support 1. FIG. 4 shows an oval 4" and FIG. 5 a round resilient hollow section 4". Both types of profiles-are filled with a predeterminable air pressure and thus can be better adapted to the use concerned, after the stack. The degree of elasticity, if required, may have an upper value very-close to that ofa rigid structure.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, andthe invention includes all such modifications.

-We claim: I

1. An apparatus for stacking a delicate thin web of material .which comprises rotatable support means having at least three resilient ribs on the surface thereof, the ribs having a length at least equal to the width of the web and a height sufficient to support the stacked web in a polygonal configuration, and a pivotally suspended rollermeans mounted adjacent to the tionally pushed away downward by loop formation of the I upper layers, despite which a transportable and storable stress-free stack is formed and delicate thin webs of material are. protected to a particularly high extent. On the other hand, lateral discs or lateral supports, such as are employed in the case of reels, and which usually would interfere with subsequent processing of the stack are advantageously eliminated.

As shown in FIG. I, a web of material 5 is conveyed over a roller 10 toa stack 2 and stacked there. Conveying the web of material 5 over the ribs 4 and the continuous ply'on the stack 2 results in different distances with respect to the axle 11, causing corresponding speed differences which are compensated by a roller 6 movable in the swinging arms 8. A condition is thus provided for the trouble-free stacking of the succeeding layers-on the stack 2. The stack 2 is formed by rotating the support 1 about the axle ll.

rotatable support means whereby speed and stress differences of the web occurring when passing over the ribs are compensated by the roller means over which latter the web passes prior to contact with the rotatable support means.

2. An apparatus according to claim I in which the ribs are provided with dimensionally stable surfaces.

3. An apparatus according to claim 2 in which the ribs have a circular cross section.

4. An apparatus according to claim 2 in which the ribs have a semicircular cross section.

5. An apparatus according to claim 2 in which the ribs have a angular cross section.

6. An apparatus according to claim 2 in which the ribs have an oval cross section.

7; An apparatus according to claim 2 in which the ribs are hollow. I

8. An apparatus according to claim 1 including means for advancing the center of the rotatable support means, whereby a distance of a few centimeters is maintained between between material on the support means and the roller means.

9. An apparatus according to claim 1 in which the width of the web is at least equal to the height ofthe stacked material.

10. A process for stacking a delicate thin web of material which comprises passing the web over a pivotally suspended roller and then onto a rotatable support having at least three resilient areas on the surface thereof in contact with the web and serving to support the stacked web in a polygonal configuration, the speed and stress differences of the web occurring when passing over the resilient areas being compensated by the roller. 

